1. FIELD OF THE INVENTION
This invention relates to the preparation of hydrogen peroxide by acid catalyzed hydrolysis of tertiary butyl hydroperoxide.
2. DESCRIPTION OF THE PRIOR ART
U.S. Pat. No. 3,737,518 describes a method for producing hydrogen peroxide and alcohol by reacting an organic hydroperoxide and water at a temperature of from 60.degree. C. to 130.degree. C. in an aqueous acid solution containing from 1 to 40 wt. % acid. Concentrations of the organic hydroperoxide can be from about 1 to about 50 wt. % based on the reactants, depending on the particular system used. The hydroperoxide reacts with the water on an equal molar basis to produce 1 mole of hydrogen peroxide and 1 mole of alcohol. Tertiary butyl hydroperoxide is disclosed as a suitable organic hydroperoxide reagent.
U.S. Pat. No. 3,891,748 discloses an acid catalyzed process for the production of hydrogen peroxide from tertiary butyl hydroperoxide wherein tertiary butyl hydroperoxide is continuously contacted with water in the presence of an acid in a contacting zone operated under conditions such that tertiary butyl alcohol product is continuously removed overhead and hydrogen peroxide is recovered from the bottom stream. A suitable contacting zone is a fractionating column with a reboiler system provided at the bottom of the column. Aqueous acid solution is introduced at the upper end of the fractionating column and tertiary butyl hydroperoxide is introduced at the lower end of the column. A mixture of unreacted tertiary butyl hydroperoxide, tertiary butyl alcohol, water, and volatile organic by-products is recovered overhead. Most of the reaction occurs in the fractionating column employed in the U.S. Pat. No. 3,891,748 process.
The method of the U.S. Pat. No. 3,891,748 minimizes the usual side reactions associated with acid catalyzed hydrolysis such as the reaction of tertiary butyl alcohol with hydrogen peroxide or with tertiary butyl hydroperoxide to form di-tert-butyl peroxide. See the following equation: ##STR1## A key advantage of the U.S. Pat. No. 3,891,748 process is that it allows tertiary butyl alcohol to be stripped from the reaction zone as it is formed, driving the hydrolysis reaction towards completion. However, production of nonselective co-products--noteably di-tertiary butyl peroxide--remains a problem. Additional disadvantages of these prior art methods are moderate hydrogen peroxide selectivities and the low concentration (less than 1 wt. %) of hydrogen peroxide in the aqueous product stream recovered from the reaction zone.
Accordingly, an object of the present invention is an improved method for producing hydrogen peroxide by the acid catalyzed hydrolysis of tertiary butyl hydroperoxide. A further object is the conversion of tertiary butyl peroxide with enhanced selectivities to the hydrogen peroxide product and to desirable tertiary butyl alcohol and isobutylene by-products. A still further object is an acid catalyzed hydrolysis process which produces a more concentrated hydrogen peroxide product stream.